The objective of this Resource is to continue to provide high quality biofluid analyses for tobacco biomarkers using state-of-the-art methods and instruments. This Resource supports numerous NIH- funded biomedical research projects, mostly human clinical studies of tobacco addiction and its treatment. It will also support studies of secondhand smoke exposure. This application seeks funds to purchase a replacement for an obsolete instrument, and allow our facility to support numerous commitments for biofluid analyses for investigators at our institution and throughout the US. For reasons of analytical sensitivity, specificity, and to be able to analyze large numbers of samples (about 5000-10,000 per year), most of our analyses are carried out using liquid chromatography - tandem mass spectrometry (LC-MS/MS). All of these methods have been developed in our laboratory and some are not available elsewhere. Two of our methods are in particularly high demand: (1) Simultaneous determination of the nicotine metabolites cotinine and trans-3'- hydroxycotinine. The ratio of these metabolites in biofluids can be used to phenotype for the nicotine- metabolizing enzyme CYP2A6, and is highly correlated with the rate of nicotine elimination from the body (Dempsey et al, Nicotine metabolite ratio as an index of cytochrome P450 2A6 metabolic activity. (Clin Pharmacol Ther. 2004;76:64-72.). This ratio has been used to individualize pharmacotherapies for tobacco dependence (Lerman et al., Nicotine metabolite ratio predicts efficacy of transdermal nicotine for smoking cessation. (Clin Pharmacol Ther. 2006;79:600-8.). The metabolites are routinely measured in plasma, serum, urine, and saliva. (2) (4-(Methylnitrosamino)-1- (3-pyridyl)-1-butanol), NNAL, a tobacco-specific carcinogen metabolite. It can be measured in urine of smokers or of non-smokers exposed to secondhand smoke (SHS). This is probably the best biomarker for SHS exposure, due to its long biological half-life, by providing a time-averaged measure of exposure when exposure patterns are erratic (Eisner, MD, Jacob, P, 3rd, Benowitz, NL, Balmes, J, Blanc, PD. Longer-term exposure to secondhand smoke and health outcomes in COPD: impact of urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) Nicotine and Tobacco Research, in press). The research projects supported by our resource seek to improve public health by furthering our understanding of tobacco addiction and developing improved treatment modalities, including individualizing treatment using pharmacogenetic approaches. Some supported projects involve tobacco toxicology, such as exposure to secondhand smoke and specific carcinogens. Our resource is also available for non-tobacco related projects, but the majority our funded studies and collaborators studies are in the tobacco field. PUBLIC HEALTH RELEVANCE: About 500,000 Americans and about 5,000,000 people worldwide die each year from tobacco related diseases. The research projects supported by our resource are developing improved therapies for tobacco addiction, or are investigating exposure to secondhand tobacco smoke in order to reduce its adverse health consequences.